1. Technical Field
The present invention relates generally to the field of renewable energy. Still more particularly, the illustrative embodiments are directed to an integrated process and apparatus for an integrated wind-solar energy system utilizing an existing wind turbine infrastructure.
2. Background
A wind turbine as a source of renewable energy in the form of electricity is attractive. However, the wind turbine has drawbacks that at times it is not able to produce sufficient energy due to insufficient wind velocity to drive the turbine blades. Since wind energy is unreliable, the capacity factor for most wind turbine farms in the United States is less than 40%. The wind turbine farm has clusters of wind turbines that are isolated from each other, and each cluster experiences a slightly different wind speed and turbulence. A typical 100 Mega Watt (MW) wind turbine farm will generate less than 20 MW during the summer months in a critical afternoon peak demand energy period. This problem currently exists for the 8000+ MWs of wind turbines in West Texas, which has the largest concentration of wind turbine energy production in the United States.
Solar energy appears to be a solution to the reduced output of wind turbine energy during the daytime. The solar energy is available for about 6 hours per day during the late morning to late afternoon hours. It is known that solar energy tends to provide maximum output energy during the summer months, and the least during the winter months, just the opposite of wind turbine energy. The problem with the normal isolated solar energy array system is that it requires hundreds of acres of relatively flat level land with a completely independent and fully integrated generation infrastructure, which includes a manned facility with a control building, control system, multiple inverters and combiners, one or more step up transformers, switchgear, substation and a special access transmission tie line to the nearest transmission grid.
Presently, solar energy resources may be allocated to a transmission grid in a way that is not fully integrated because solar energy is not considered a reliable source of energy. The solar energy farm array limited energy availability requires special transmission grid management to handle the sudden onset and reduction of a block of solar energy to the transmission grid. The availability of solar energy is limited due to the reason that solar energy is only generated when the sun is shining.
The wind energy farms are usually located on private land or ranches and typically utilize irregular terrains, which usually are the locations of the best wind velocities. A typical wind energy farm is usually a cluster of wind turbines on various hills. The land around the wind turbine includes a network of towers, access roads, underground electrical conduits, possibly the rancher's cattle, and most certainly the wild animals. A large segment of the ground area around the wind turbine tower is for the equipment, lay down areas for maintenance, access for the large tower cranes needed for rotor blade, and power train removal and replacements. This invention effectively supplements the energy produced by a wind turbine and overcomes the lack of land space around a wind turbine farm or individual wind turbine by providing a method and system for an integrated wind-solar system utilizing an exiting wind turbine infrastructure, as no separate solar energy array land space is required. This tower mounted Photovoltaic (PV) solar array actually protects the solar panels from physical damage. This invention also avoids the grid integration requirements normal to a solar energy array farm, because it only represents a small percentage (about 25 KW vs. 1.5-2.5 MW nameplate of the connected wind turbine) of the actual wind turbine energy output under normal conditions.